Organic binders for composite fiber products such as fiberglass insulation are moving away from traditional formaldehyde-based compositions. Formaldehyde is considered a probable human carcinogen, as well as an irritant and allergen, and its use is increasingly restricted in building products, textiles, upholstery, and other materials. In response, binder compositions have been developed that reduce or eliminate formaldehyde from the binder composition.
One type of these formaldehyde-free binder compositions rely on esterification reactions between carboxylic acid groups in polycarboxy polymers and hydroxyl groups in alcohols. Water is the main byproduct of these covalently crosslinked esters, which makes these binders more environmentally benign, as compared to traditional formaldehyde-based binders. However, these formaldehyde-free binder compositions also make extensive use of non-renewable, petroleum-based ingredients. Thus, there is a need for formaldehyde-free binder compositions that rely less on petroleum-based ingredients.
As an abundant and renewable material, carbohydrates have great potential to be an alternative to petroleum-based binders. Carbohydrates are already used as a component of some types for binders, such as Maillard binders that contain reaction products of reducing sugar carbohydrates and amine reactants. Although these products may have acceptable thermal and mechanical properties for low density fiber glass products, their fire resistance is typically lower than formaldehyde containing resins for pipe insulation and other high density fiberglass-based products. Thus, there is a need to improve the fire resistance of carbohydrate-containing binder compositions. These and other issues are addressed in the present application.